rabbi1

the chief religious official of a synagogue, trained usually in a theological seminary and duly ordained, who delivers the sermon at a religious service and performs ritualistic, pastoral, educational, and other functions in and related to his or her capacity as a spiritual leader of Judaism and the Jewish community.

"Jewish doctor of religious law," late 15c. (in Old English in biblical context only; in Middle English also as a title prefixed to personal names), from Late Latin rabbi, from Greek rhabbi, from Mishnaic Hebrew rabbi "my master," from rabh "master, great one," title of respect for Jewish doctors of law + -i, first person singular pronominal suffix. From Semitic root r-b-b "to be great or numerous" (cf. robh "multitude;" Aramaic rabh "great; chief, master, teacher;" Arabic rabba "was great," rabb "master").